A vehicular headlamp is constituted by a lamp unit disposed in an external case of a lamp constituted by, for example, a cover and a lamp housing. The lamp unit includes a lens unit having a projection lens that projects light emitted from a light source to project the light to the front and a lens holder that holds the projection lens.
A vehicular headlamp may have a heat sink for dissipating heat generated when a light source is driven, that is, when light is emitted from the light source. See, for example, Japanese Patent Application Laid-Open No. 2008-257959.
An aiming adjusting mechanism that adjusts a direction of an optical axis at the time of delivering or examining a vehicle is provided in the vehicular headlamp and an aiming operating shaft of the aiming adjusting mechanism rotates in a circumferential direction of the shaft to rotate the lamp unit in a vertical direction or a horizontal direction, thereby adjusting the direction of the optical axis.
In the vehicular headlamp disclosed in Japanese Patent Application Laid-Open No. 2008-257959, the lens unit and the heat sink are attached to a frame disposed inside the external case of a lamp and the heat sink protrudes rearward from a protrusion hole formed in the lamp housing. The aiming operating shaft is screw-joined to the frame and the aiming operating shaft rotates to integrally tilt the frame, the lens unit and the heat sink, thereby adjusting the direction of the optical axis.
In the vehicular headlamp, the heat generated when the light source is driven is discharged to the outside through the heat sink that protrudes rearward from the lamp housing to ensure an excellent heat dissipating performance. The heat generated when the light source is driven is discharged to the outside to suppress an increase in temperature of the light source, thereby ensuring a normal driving state of the light source.